Cluster gear and method of manufacture therefor



Dec. 21 1943. AMMQN 2,337,222

CLUSTER GEAR AND METHOD OF MANUFACTURE THEREFOR Filed Aug. 2, 1940 2 SheEts-Sheet 1 INVENTOR.

ATTORNE Y.

Dec. 21, 1943. M. A. AMMON CLUSTER GEAR AND METHOD OF MANUFACTURE THEREFOR Filed Aug'. 2, 1940 2 Sheets-Sheet 2 INVENTOR. MfiEK fi. HMMUN m mH m Mi n A HW -UHWWILHH By'mmjz w ATTORNEY.

Patented Dec. 2-1,

CLUSTER GEAR- AND METHOD OF,

THEREFOR Mark A. Amman, Peoria, 111., minor to Caterpillar-.Tractnr 00., San Leandro, Calif a corporation of California Application August 2, 1940, Serial No. 349,692

a claims. (01. 29-1593) My invention relates to forging, and more particularly to forging of an integral cluster gear,

or similar article, having a'plurality of gears integral with a hub and a groove between adjacent gears,

With respect to a cluster gear designed for shifting movement along a speed-change transmission shaft, the groove between adjacent gears is usually comparatively narrow to receive a suitable shifting fork; and the narrowness of such groove presents-the problem of forging adjacent gears with proper metal flow-line characteristics. This is so because it is extremely diflicult to provide in'the forging apparatus a. narrow or thin insert collar 'or.ring adapted to form a groove during forging, which is of a material that will not deform under the forging temperature. Obviously, such deformation is objectionable inasmuch as, if occurring, it would preclude proper formation of the parts.

Heretofore,-this .diiiiculty was. overcome by manufacturing suchcluster gear by a-forging machine method which broadly comprises feed ing arelatively long bar of the stock in a horizontal direction, upsetting. the stock to form a blank for one of the'gears and a shank portion for another adjacent gear, and then subsequently upsetting the shank portion -by folding-the material adjacent suchflrst formed blank, against itself, to form, the blank for the adjacent gear, and a lap or fold between'such blanks, which is subsequently machined out. In .such forging machine, the dies part longitudinally or axially with respect to the stock; and the blank for the smaller gear of the cluster gear is formed prior to the formation of the lap and the blank for the larger gear. Asa result, the forging parting line resulting from the dies will extend longitudinally or axially which is not at all to be desired,

as this does not enable best flow line characteristics. Furthermore, the formation of the lapand I the blank for the larger gear after formation of the lap and the blank for the larger gear after formation of the blank for the smaller gear, is not entirely satisfactory because such procedure,

makes it extremely dlfflcult to control the location of the lap which frequently forms in the blank portion for the larger gear, resulting in weakening of the structure when the lap is :ma-'

chined out.

My invention is designed to: overcome the above described problems and has as its objects, among others, the provision of an improved and-economical forging method for a cluster gear or similar article, whereby the formation of the-described lap is accuratelycontrolled, and proper flow line characteristics are imparted to the gear to thus form an improved article; and which'may also be employed to advantage for formation of a cluster gear or similar article which is not formed with such lap, during manufacture, but to which favorable flow line characteristics are imparted by the method. Other objects of my inventionwill become apparent from a-perusal of the following description thereof, In general, my invention comprises first form-j ing a blank for the-larger gear of such cluster gear, by die means which applies axial pressure and provides a parting line which extends transversely with respect to the peripheral or sear tooth-face of the-blank intermediate the sides thereof, and then applying pressure on the ma terial in an axial direction to upset the material adjacent the blank and form another gear blank for a smaller gear. Because of the arrangement of the parting line in the manner related, good flow line characteristics are imparted to the larger gear; When the cluster gearis to have,

the comparatively narrow groove, a collar is employed about the material to be upset for formation of the blank for the smaller gear adjacentthe blank for the larger gear, and during such upsetting a lapis allowed toform. By this means, the location of the lap may be accurately controlled sees not to come within the blank for the larger gear. Substantially the same method is employedfor a cluster gear which has a relatively wide groove between adjacent gears, except that the blank forthe smaller gear is formed by upsetting the material adjacent the blank for the larger gear, within asplit collar or die having an internal ring toform the widegroove, and which maybe readily removed after formation of the smaller gear.

Reference is now made to the drawings for a w more detailed description of the invention.

Fig. l is a longitudinal sectional view of one form of a narrow groove cluster gear, chosen for purposes of illustration. to. which the method of my invention is applicable..

/ Figs. 2 through 8 are schematic views illustrat-f ing in progressive stages the method of forming the gear of Fig. 1. v

' Of theseflg'ures:

Fig. 2 is a perspective view of a stock or mass of material from which the gear is made.

Fig. '3 is an elevational view of such mass after it is given a, preliminary shaping.

Fig..,4 illustrates a roughing impression'made :by a forging hammer.

Fig. illush'ates the flnal hammer forging impression.

Fig. 6 illustrates the blank in the apparatus employed for effecting formation of the blank for the smaller gear and the previously mentioned lap, just prior to the formation thereof.

Fig. 7 illustrates the apparatus and the shape of the blank of Fig. 6, after formation of the blank for the smaller gear and the lap.

Fig. 8 illustratesthe blank of Fig. '7 removed from the apparatus and rough machined; the blank being shown in longitudinal section, and with the metal flow line formation on-one side.

round stock. However, round orany other suit-' ably shapedstock may be employed if so desired. Such mass H is heated in any suitable manner to a suitable forging temperature, and is then preliminarily shaped by any suitable means, to

elongate an end portion l2 and round the mate- -rial as is indicated i'nFi'g. 3.

Next, a roughing impression is made the blank of Fig. 3 in an upright position in die [3 which cooperates with vertically movable forging hammer "to form blank l5 for larger diameter gear 3, and shank portion n.

It is to be noted that pressure is applied to the material,

Fig. 9 is a longitudinalsectional view of one form of a wide groove cluster gear, chosen for purposes of illustration, to which the method of my invention is applicable.

Figs. 10 through 18 are schematic views illustrating in progressive stages the method of forming the gear of Fig. 9. Of these figures:

Fig. 10 is a perspective view of a stock or mass of material from which the gear is made.

Fig. 11 is an elevational view of such mass after it is given a preliminary shaping.

Fig. 12 is an elevational view of such mass after it is given a second preliminary shaping. Fig. '13 illustrates a roughing impression made by a forging. hammer.

. Fig. 14 illustrates the final hammer forging impression.

Fig. 15 illustrates the blank in the apparatus employed for effecting formation of the blank for the smaller gear and the wide groove, just prior to the formation thereof.

Fig. 16 is a section taken in a plane indicated by line l5l6 in Flg. 15.

Fig. 1'7 illustrates the apparatus and the shape of the blank of Fig. 15, after formation of the by hammer ,in an axial direction, and that die I3 and hammer ll are so related as to provide forging parting line B intermediate the sides of blank l6 and transversely with respect to the peripheral or gear tooth face l8 of such blank. This is an important factor for causing the metal flow lines F for the larger diameter gear to extend radially adjacent each side of the gear, to provide for maximum strength. 1

After formation of the blank illustrated in Fig. 4, it is next hammer forged, by means similar to that illustrated inFig. 4, to form a final hammer forging impression. Such final hammer forging impression is illustrated in Fig. 5, from which it can be seen that the contour of gear blank l6 and shank portion H are somewhat changed, but die I9 and vertically movable forging hammer 2|, which provides pressure in axial direction, still cooperate to maintain parting line blankfor the smaller gear and the wide groove.

Fig. 18 illustrates the blank of Fig. 17 removed from the apparatus; the blank being shown in longitudinal section, and with the metal flow line formation on one side.

With reference to Fig. 1, the cluster gear is of integral construction and comprises hub 2 having large diameter gear 3 provided with teeth 4 on its peripheral or tooth face, and smaller diameter gear 5 provided with teeth on its toothface.

' Between the gears is a comparatively narrow annular groove 8 which is adapted to receive a shifting fork. The inside of hub 2 is provided with splines 8 to provide for mounting of the gear .for rotatable movement with and axial movement along a transmission shaft. It is desirable that the gear be a steel forging for strength. Also, for a maximum strength, it is desirable that the metal flow lines resulting from the forging extend substantially radially adjacent each side of each gear of the cluster gear,

as is indicated by the flow lines F in Fig. 8. This.

is so because maximum stresses are imparted to a gear" in a radial direction, and radially extending flow lines enable the metal to withstand such forces.

The method of my invention produces such favorable flow line effect, and comprises utilizing a predetermined amount of a stock or mass of material to provide suflicient material for the formation of a single cluster gear, in contradistinction to the previously mentioned forging .machine method wherein a long bar'of stock is utilized for making a plurality of cluster gears therefrom. As is indicated in Fig. 2, the stock or mass of material II is preferably rectangularly shaped as this is more economical than P at the desired location intermediate the sides of blank I6 and transversely with respect to gear tooth face l8 thereof. In the forging dies of Figs. 4 and 5, it is necessary to form so-called draft on the face 18 to enable the dies to be readily separated. After the shaping illustrated by Fig. 5, the "draft is removed by any suitable means (not shown) to straighten face I8, as is illustrated by the vertical dotted lines 22 in Fig. 5.

The blank of Fig. 5 after removal of the draft,

is now ready for the formation of the smallergear blank and th lapto which reference has been made.

For the'latter purpose, such blank is placed in die 23 in which it fits closely, and the upper edge 24 of which lies substantially flush with the upper side 25 of gear blank l6. An integral solid collar 21 is next properly centered loose about shank portion H to provide annular space 28 therebetween to allow for upsetting of material from shank portion 11; the collar 21 resting on top edge 24 of die: 23 and on upper side 26 of the gear blank l6. As a result, when axial pressure is applied to shank [1, gear blank it will main- .diameter is formed first, less material need be worked for forming the blank 3| for the gear of lesser diameter. This factor in associationwitli collar 21, enables the-location of lap 32 to be definitely'controlled so as to form without, and

not within the blank portion It for larger gear 3, 'as has heretofore occurred with respect to the by placing previously related forging machine method. As

a result, when material is machined out to form groove 8, none of the materi al'of blank It need be removed ad acent the hub portion, which if occurring would weaken the. structure. Fig. 8 illustrates. the blank after th shaping illustrated in Fig. 7, partially machined to provide groove 8, and having hub aperture 33 which is subsequently punched out in any suitable manner. The finished cluster gear of Fig. 1 is made from the blank of. Fig. 8 by usual machining operations.

From the preceding description, it is seen that the cluster gear of Fig. 1 is made essentially by first forming the blank for the larger gear by hammer forging in an axial direction, and then the smaller gear ismade by upsetting through a pressing operation in an axial direction. These two steps also cooperate in association with the particular arrangement of the parting lin P to provide flow lines F which extend radially ad- J'acent each side of each gear, to insure maximum strength.

Fig. '9 illustrates another form of cluster gear having a relatively wide groove 4| between large diameter gear 42 and smaller diameter gear 43. Because of the relatively. large size of groove 4|, it may be made during forging by meansof an insert ring, without the necessity of forming a lap or fold of the material. This i so because the insert ring will have sufficient metal to enable 30 it to withstand the forging temperature. However, the gear is otherwise made substantially the same as the gear of Fig. 1, to obtain the advantages resulting from such method.

As with respect to the method formaking the gear of Fig. 1, the gear of Fig. 9 is preferably made from a predetermined amount of a stock or mass of material 44 which for economy is, preferably, rectangularly shaped, but which may be any other suitable shape. Such stock or mass is heated, and preliminarilyshap'ed in any suitable manner to round the comers thereof and elongate one end 46, as is illustrated in Fig. 11. Next, the bottom 41 is upset, inany suitable way, to shape the material in the manner illustrated in Fig. 12. A roughing impression 48 is then made by hammer forging, as is illustrated in Fig. 13, by means of bottom die 49 and upper verticalhr movable forging hammer which re- -sults in the formation of blank 52 for larger 50 gear 42, in which parting 1ine.P is between the sides of the blank and transverse to the perip eral or tooth face 53 thereof.

Fig. 14 illustrates a final forging impression 54 which is next formed by hammer forging in 55 lower die 56 cooperating with vertically movable hammer die 51 the forging parting line P in blank 52 remaining the same. After formation of the final impression 54, it is ready for formation of the blank for smaller gear 43, which is performed by a pressing operation in'the 'manner illustrated in Figs. through 17. However, before such pressing operation, the peripheral face 53 of gear blank 52 is first straightened in any suitable manner, to remove the draft, as i indicated by the dotted lines 58. s

In the pressing operation a split dieor collar comprising the two parts 59 having inner peripheral ring portion 6| is employed to form groove 4|. The final hammer forging impression 5 is positioned on lower die 62.; and split die parts 59 are also supported on lower die '62 with shank 63 passing loose through split die parts 59, as is illustrated in Figs. '15 and 16. A wedge 64 is provided between each die part 59 of the die and a fixed abutment 86. As a result.' when forging press member 61- is moved downwardly to apply axial pressure, the metal of shank 63 is upset to form the blank 68 for 5 smaller gear 43, as is illustrated in Fig. 17. During such operation, the shape of gear blank 52 remains substantially the same. Because of the split character of the die in which shank 63 is upset, it may be readily removed when the 1 smaller gear blank 68 is formed; and the forg- 15 of Fig.'18 are also favorable by virtue of the described procedure, inasmuch as the flow lines extend substantially radially adjacent each side of each gar to impart strength to the peripheral or tooth face thereof; This is particularly so with respect to theflow line effect at point A,

namely the lower peripheral edge of the smaller gear'43, because of the upsetting of shank por- ,tion 63 over inner peripheral ring 6|. The employment of inner peripheral ring iii to form groove 4|, is also advantageous because of the saving of metal inasmuch as less material is required in the original stock-44.

v Although the method of my invention is particularly applicable to the manufacture of an integral structure comprising a hub and a plurality of adjacent gears, it will be apparent from the preceding description that it is equally applicable to any similar article having only one gear and another radially projecting member spaced therefrom, or a hub having 'spaced radially projecting members.

I claim: 1. The method of making an integral cluster structure having a. plurality of closely adjacent members integral with a hub, which comprises forging from a mass of. material a blank for one of said members while providing a forging parting line which extends transversely with respect to the peripheral face .of said blank and intermediate the sides thereof, and then forming another blank for another of said members closely adjacent but spaced from said first mentioned blank and simultaneously folding material bespaced from said first mentioned blank toward said other blank; the procedure for folding said 2. As an article of manufacture, a forged integral cluster gear having a plurality of gears integral with a hub and a groove therebetween, oen of said gears being characterized by formation of a forging parting line extending transversely with respect to its tooth face and intermediate the sides of such gear.

3. As anarticle of manufacture, a forged integral gear blank structure having a hub, a gear 70 blank integral with said hub, another blank member integral with said hub, and a lap located withoutsaid gear blank; said gear blank having radially extending flow lines adjacent each side thereof to provide strength for the gear tooth :5 face of said blank, and a forging parting line tween said blanks upon itself and thereby forming a lap adjacent said first mentioned blank therebetween,

extending transversely with respect to said face and intermediate the sides of said gear blank.

"4. :As an article of manufacture, a forged integral cluster gear having a plurality of different size gears integral with a hub .and a groove a larger of said, gears having radially extending flow lines adjacent each side thereof to provide strength for the tooth iace thereof characterized by formation of a forging parting line extending transversely with respect to said face and intemediate the sides of said gear, and an adjacent smaller gear also having I ,having radially extending flow lines adjacent each side thereof to provide strength, and the larger of said blank members having a-forging parting line extending transversely with respect 'to its peripheral face and intermediate its sides.

6. The-method of making an integral cluster structure having a plurality of closely adjacent members integral with a hub, which comprises forging from a mass of material a blank for one of said members while providing a forging parti'ng line which extends transversely with respect to the peripheral face of said blank and intermediate the sides thereof, then forming another blank for another of said members closely adjacent but spaced from said first mentioned blank and simultaneously folding material between said blanks upon itself and thereby forming a lap adjacent said first mentioned blank spaced from said first mentioned blank toward said other blank; the procedure for folding said material and forming said' other blank and said' lap comprising applying pressure on said mass forming said other blank axially toward said first mentioned blank while providing limited fold-forming freedom for the material between said blanks, and confining the material to form said other blank, and then removing the material adjacent said lap,

.MARK A. AhflVION.

CERTIFICATE OF CORRECTION. Patent No. 2,557,222. December 21', 19h5.

MARK A. Armon.

It is hereby certifiedi'that error appears in the printed specification of the above numbered patent requiring correction as follows Page 1 ,'first column, lines 15 and 1 1+, strike out the word; "18 and the blank for the larger g ear after formation of the"; page 5, second column, line 65, claim 2, for "oen read ,-one--; page 1;, first column, line 11, claim 14., for.

"intemediate" read intermediate--; and that the said Letters Eatent should be read-with this correction therein that the same may confom to the record of the caee in the Patent Office.

Signed and sealed this 9th ma of Hey, A. 1). 19%.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

